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Conversion of lignin-derived molecules into value-added chemicals is critical for sustainable chemistry but still challenging. Herein, phosphorus-modified palladium catalyzed the degradation of lignin-derived 4-O-5 linkage to produce KA oil (cyclohexanone-cyclohexanol oil) was reported. The reaction proceeds via a restricted partial hydrogenation-hydrolysis pathway. Phosphorus-modified palladium catalyst suppressed the full hydrogenation of diary ether, which was the key point to produce KA oil selectively. Under the optimized conditions, the 4.5 nm Pd-P NPs could catalyze the conversion of 4-O-5 linkage into KA oil in 83% selectivity with a high production rate of 32.5 mmol·g−1 Pd ·min−1. This study represented an original method for KA oil production. [Display omitted] • Pd-P/C catalyzed the lignin-derived 4-O-5 linkage to produce KA oil. • Phosphorus modified Pd suppressed the full hydrogenation of diphenyl ether. • KA oil was obtained in 83% selectivity over 4.5 nm Pd-P NPs. • A partial hydrogenation-reductive hydrolysis tandem route was proposed. [ABSTRACT FROM AUTHOR]

Porous carbon spheres materials display huge potential for energy storage, but their general synthesis need chemical activation agent with highly corrosive to create pores. In this work, a simple, environment-friendly and less time-demanding method is used to prepared porous carbon spheres using K 2 FeO 4 as activation agent and waste solution as the precursor. The K 2 FeO 4 employ in this work acts both as an activating agent and a catalyst. In addition, replacing KOH with K 2 FeO 4 does not only reduce the corrosion of equipment but also increases the content of oxygen. The optimized porous carbon spheres with high specific surface area, hierarchical pore structure and surface heteroatom can deliver a high specific capacitance of 260 F g−1 at 0.1 A g−1 and good cycling stability (90% retention after 15000 cycles at 5 A g−1). Furthermore, the all-solid-state symmetric supercapacitors fabricated based on as-prepared samples exhibit good electrochemical performance in the PVA/KOH electrolyte. This work offers a green route to convert waste solution into porous carbon spheres, which are promising candidate material for supercapacitors to energy storage. • K 2 FeO 4 is used as an activating agent and a catalyst during the activation process. • Porous carbon spheres is prepared from waste solution. • PCS-T-R based all-solid-state supercapacitors possess good electrochemical properties. [ABSTRACT FROM AUTHOR]

Waste sugar solution (WSS), a waste by-product of manufacturing vitamin C, contains abundant waste acids and organics. In this work, a N/O -enriched copolymer was synthesized via a facile polymerization via the hydrogen bonding of O -containing functional groups and melamine and the crosslinking of aldehyde groups. Subsequently, N -doped carbon spheres were prepared by a typical carbonation/activation method. Remarkably, benefiting from an ultrahigh specific surface area (3612 m2/g) and rich heteroatom content (4.3% for N, 8.8% for O), the carbon spheres deliver a high specific capacitance of 387 F/g at 50 mA/g and 283 F/g at 5 A/g with 6 M KOH in two-electrode system. The assembled symmetric electric double-layer capacitor exhibits high energy density of 10.83 Wh/kg at 11.10 W/kg. This research provides a facile method for preparing N / O -doped carbon spheres by WSS, and confirms the excellent electrochemical performance of WSS-derived carbons in energy storage applications. [Display omitted] • N-doped carbon spheres are prepared by waster sugar solution. • Two nitrogen doping strategies are compared and discussed in detail. • The as-prepared samples display good electrochemical performance. [ABSTRACT FROM AUTHOR]

Waste sugar solution is a by-product in the process of manufacturing vitamin C. Nowadays, the unused industrial waste residues are transformed into high efficient energy storage devices, such as supercapacitors electrodes, which are worth exploring because they are consistent with the concept of green and sustainable development. In this paper, a nitrogen-doped hierarchical porous carbon are obtained via pre-carbonization and KOH activation. The as-prepared material, possessed proper pore size distribution, large specific surface area and nitrogen-doping, exhibits good electrochemical performance, such as a high specific capacitance of 342 F g−1 (0.1 A g−1), good stability with 95% capacitance retention after 15,000 cycles in 6 M KOH. Moreover, the supercapacitors deliver a high energy density of 25.6 and 65.9 W h kg−1 in the 1 M Na 2 SO 4 and EMIMBF 4 , respectively. The good electrochemical performance illustrates that the nitrogen-doped hierarchically porous carbon derived from the waste sugar solution is a potential candidate for energy storage. Image 1 • Nitrogen-doped hierarchically porous carbon were derived from the waste product. • NPCs have good electrochemical performance in aqueous electrolytes and ionic liquids. • The energy density reach up to 25.6 and 65.9 W h kg−1 in the 1 M Na 2 SO 4 and EMIMBF 4. • The NPCs electrode shows good rate performance and better cycling stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coal tar pitch was oxidized by KMnO 4. • Nitrogen precursors were synthesized by chemical oxidative polymerization. • Nitrogen-doping three-dimensional hydrangea-like porous carbons was prepared. • High energy density (56.4 Wh kg−1) in EMIMBF 4 electrolyte. Nitrogen-doping three-dimensional hydrangea-like porous carbons (NHPCs) were prepared by coal tar pitch oxidized by KMnO 4 (OCTP) as carbon precursor and p-phenylenediamine (pPDA) as nitrogen source. The terminal amine group on the pPDA and the oxygen-containing functional group on the OCTP were grafted together by chemical oxidative polymerization. Not only successfully achieved nitrogen-doping, but also the benzene ring in pPDA could occupy the branching space of polycyclic aromatic hydrocarbons in OCTP and reduce its irreversible accumulation. The as-prepared NHPCs showed a unique three-dimensional hydrangea-like structure, which could provide large specific surface area (2237 m2 g−1), abundant micro/mesopores and high nitrogen content (3.7%). Remarkably, NHPC-600 exhibited excellent electrochemical performance as the electrode material of supercapacitors, such as a high specific capacitance up to 423 F g−1 at 0.1 A g−1 and long cycle stability (maintaining 94.3% of the initial capacitance after 10,000 cycles) in 6 M KOH. Simultaneously, NHPC-600 achieved a higher working voltage (3.6 V) in EMIMBF 4 electrolyte, thereby obtaining a high energy density (56.4 Wh kg−1). [ABSTRACT FROM AUTHOR]

Due to the interconnected network and high porosity, melamine foam has been selected as the template to obtain hierarchical porous carbon. In this paper, porous carbon with hierarchical porous structure, high pore volume and high specific surface area is prepared by using melamine foam as template and waste liquid (from the production of vitamin C) as carbon precursor coupled with KOH-activation. Owing to these favorable structural characteristics, the supercapacitors electrodes based on the as-prepared products have outstanding electrochemical performances in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF 4) electrolyte. The optimized electrode (WMFPC 700-5) reaches a high specific capacitance (217 F g−1 at 0.1 A g−1) and superior cycling stability (specific capacitance retention of 89% after 10000 cycles at 5 A g−1). Notably, supercapacitors displays an ultra-high energy density of 107 Wh kg−1 at a power density of 94 W kg−1 in EMIMBF 4 electrolyte system. In addition, the all-solid-state symmetric supercapacitors based on WMFPC 700-5 demonstrates a remarkable specific capacitance of 180 F g−1 at 0.5 A g−1 in the EMIMBF 4 /PVDF-HFP gel polymer electrolyte. [ABSTRACT FROM AUTHOR]